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New GTIA chips!


Curt Vendel

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*Lightbulb moment*

 

Relating to improving video on Atari machines

 

How about a GTIA that outputs raw RGB. VBXE does so but is too expensive for someone who doesn't want the full featureset.

Then again, maybe it'd be less effort/expense to just have a cut-down VBXE which only has the GTIA features and RGB output.

 

Pokey is another area of interest. Something like Quad Pokey in a single package would be pretty awesome. Or maybe something like a dual-Pokey, plus quad 16-bit DACs on a small board with dedicated RAM.

An updated PoKey would be cool, but even cooler is that we can finally have Amy? Maybe Curt's next new case after the 1200XL one could be a 65XEM :lust:

 

Stephen Anderson

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I am trying to recover the Silver & Gold chipsets, the tapes are not in standard 2048 blocks and I block by block view of the tape header is not revealing anything. AMY is recoverable too. There is code for something called ICY, I also recovered the SARA B chip as well, so things are coming along.

 

Curt

 

Rushes off to AHS to jog my memory on the Silver & Gold chips. Ah - the Sierra 68000. Would be awesome of these can see the light of day.

 

Stephen Anderson

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The way GDS is written to 9track reel to reel backups - called a "tapeout" is a very weird process, dd is what has been used to recover the chips so far.

 

 

 

Curt

 

... Christmas and New Years are fast approaching, so I'll look more deeply into this after New Years...

This news really puts a smile on my face. Enhanced chips would be fantastic, but even SMT versions of the originals would be greatly appreciated.

 

It's been a hard year for a lot of people, and this gives us all something amazing to look forward to the coming year! :thumbsup:

 

BTW, not sure which OS/tape-drive combo you're using, but if you can set your drive to variable block size and have "dd" handy, it's pretty straightforward to figure out the blocksize of the tape.

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If it wouldn't be too much trouble, could you post a picture of the tapes? I'd love to see them.

 

The way GDS is written to 9track reel to reel backups - called a "tapeout" is a very weird process, dd is what has been used to recover the chips so far.

 

 

 

Curt

 

... Christmas and New Years are fast approaching, so I'll look more deeply into this after New Years...

This news really puts a smile on my face. Enhanced chips would be fantastic, but even SMT versions of the originals would be greatly appreciated.

 

It's been a hard year for a lot of people, and this gives us all something amazing to look forward to the coming year! :thumbsup:

 

BTW, not sure which OS/tape-drive combo you're using, but if you can set your drive to variable block size and have "dd" handy, it's pretty straightforward to figure out the blocksize of the tape.

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I think Pokey would have an immediate large (ish) market.

 

Plenty of arcade machine owners would want them - sure, there's supposedly been an FPGA implementation but from what I've read about it, it's only a partial simulation with no Pot/Key/Serial functionality and possibly no stuff like filters and 16-bit mode.

 

A dual version would have the double benefit if made as a plugin replacement - people with multiple machines could then just buy one and be able to convert 2 machines to stereo Pokey.

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I think Pokey would have an immediate large (ish) market.

 

Plenty of arcade machine owners would want them - sure, there's supposedly been an FPGA implementation but from what I've read about it, it's only a partial simulation with no Pot/Key/Serial functionality and possibly no stuff like filters and 16-bit mode.

 

A dual version would have the double benefit if made as a plugin replacement - people with multiple machines could then just buy one and be able to convert 2 machines to stereo Pokey.

 

There was some thread some time ago about enhancing GTIA and still having it pin-compatible with existing GTIA so it can not only be used for some new Atari but also as upgrade for existing machines. I think some things mentioned were: (1) allowing missiles to use all 8-bits of GRAFm instead of 2 bits (so you have 4 replicas), (2) enabling the LSB of the 4-bit luminance for some other graphics modes, (3) using GTIA audio output as a 8-bit value instead of 1-bit since CONSOL register can take a 8-bit output. Perhaps, then POKEY can complement the GTIA audio (or I think I suggested playing missile data through the GTIA 8-bit DAC as a DMA audio channel).

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As good as Amy could have been, I don't see a lot of point trying to recreate it.

Supposedly, Atari themselves couldn't get it working properly so a modern-day scenario might work out similarly.

 

I think a better solution would be a "Clever multi-channel DAC" that could do FM synthesis as well as RAM-based wavetable/sample playback at variable rates. Dedicated RAM of course so that there'd be no contention issues to worry about.

 

Either way, it's something new and not previously supported, so it's not like there's going to be an instant software base to rely upon.

 

ed - nice idea about extra bits for GTIA missiles and sound. 4 bit luma in all modes is also something that's worthwhile (and in fact they should have had it in the first place).

Edited by Rybags
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post-23-126015971787_thumb.jpg

 

If it wouldn't be too much trouble, could you post a picture of the tapes? I'd love to see them.

 

The way GDS is written to 9track reel to reel backups - called a "tapeout" is a very weird process, dd is what has been used to recover the chips so far.

 

 

 

Curt

 

... Christmas and New Years are fast approaching, so I'll look more deeply into this after New Years...

This news really puts a smile on my face. Enhanced chips would be fantastic, but even SMT versions of the originals would be greatly appreciated.

 

It's been a hard year for a lot of people, and this gives us all something amazing to look forward to the coming year! :thumbsup:

 

BTW, not sure which OS/tape-drive combo you're using, but if you can set your drive to variable block size and have "dd" handy, it's pretty straightforward to figure out the blocksize of the tape.

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So Curt, since you now have the layouts for most of the Atari chips, would it be possible to make an FPGA-based system that would play 2600, 5200, 7800 and 8-bit games?

 

That would require extensive logic to switch out the memory maps and i/o ports. It would amount to a glorified bus controller and wouldn't be at all simple to design and implement. Though if one takes the trouble that could be implemented as plastic part that could implement fairly arbitrary mappings so you could play what if by mixing and matching Atari chips in never produced ways. It is very very fun to think about. How about a 7800 with dual POKEYs and 128K of ram that can project it's sprites onto an ANTIC+GTIA generated playfield? That that also necessitates video mixing and has no hardware collision registers between and playfield.

 

OH! and no sensible OS or memory monitor for these non-stock configs. Oh well, what is yet more fantasy engineering time?

 

So it is possible but like others I'd be happy to see this information used first just to get reproductions on modern fab, FPGA, or GAL tech up and running. THEN we can think about all the fun FrankenTaris waiting to be built.

Edited by frogstar_robot
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see this is how the atari cougar could be built, it could play all the systems.. PLUS we some how modify it to have greater memory expansion and things such as MYIDE and sio 2 usb.. and the like..

 

maybe we could convince the new owners of atari to get back in the console buisness.

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see this is how the atari cougar could be built, it could play all the systems.. PLUS we some how modify it to have greater memory expansion and things such as MYIDE and sio 2 usb.. and the like..

 

A bigger memory is fine, because that can be 100% compatible with a 64KB base memory.

 

All the other extra's: I think it is better not to implent those by default.

 

If there will be a remake of the atari 8bit line, in my opinion it is the best idea to keep that new one as close as possible to the original. That means: with a SIO port, with a parallel bus (or cartridge + eci) and with two controler ports.

 

That would be awesome.

 

Many add-ons do have a few benefits. But there are also counterparts. MyIDE is great (I'm really a big fan of that small interface), but it is one of the less compatible atari 8bit IDE interfaces around.

When the 'new born' atari 8bit does have the 'usual' ports, it is much easier to use your own beloved interfaces and devices again.

 

One other question:

Who needs a new atari 8bit? I've stored over 70 atari 8bit computers. And some of them are brandnew. I know: they won't last forever, but for the next 10-20 years I'm rather sure I'll have lots of fun with them. They are still easy to obtain here in The Netherlands. And not only here.

 

Ok... when all those existing atari 8bits are 'dead' ... a remake with new components would be very cool indeed. And when there will atari 8bit available for buying, I would certainly buy one or two. But I think it would still feel like running an emulator, even when it is NOT emulation.

 

Marius

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Wouldn't the atari-typical keyboard be the bottleneck when doing a new a8 reproduction? It could sound like a paradox, but I think reproducing these is more expensive than reproducing chips. Or we should look at another solution, f.e. look at a keyboard-interface for a PC-keyboard, but possibly the interface would be another project / challenge.

 

Anyway, exciting news :thumbsup:

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As good as Amy could have been, I don't see a lot of point trying to recreate it.

Supposedly, Atari themselves couldn't get it working properly so a modern-day scenario might work out similarly.

 

From the data sheet, my guess as to why Atari couldn't make it work has got to be either lack of manpower or just plain old ineptitude. As far as I can see, it's a pretty simple device.

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Very cool, thanks :cool:

 

post-23-126015971787_thumb.jpg

 

If it wouldn't be too much trouble, could you post a picture of the tapes? I'd love to see them.

 

The way GDS is written to 9track reel to reel backups - called a "tapeout" is a very weird process, dd is what has been used to recover the chips so far.

 

 

 

Curt

 

... Christmas and New Years are fast approaching, so I'll look more deeply into this after New Years...

This news really puts a smile on my face. Enhanced chips would be fantastic, but even SMT versions of the originals would be greatly appreciated.

 

It's been a hard year for a lot of people, and this gives us all something amazing to look forward to the coming year! :thumbsup:

 

BTW, not sure which OS/tape-drive combo you're using, but if you can set your drive to variable block size and have "dd" handy, it's pretty straightforward to figure out the blocksize of the tape.

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One other question:

Who needs a new atari 8bit? I've stored over 70 atari 8bit computers. And some of them are brandnew. I know: they won't last forever, but for the next 10-20 years I'm rather sure I'll have lots of fun with them. They are still easy to obtain here in The Netherlands. And not only here.

 

Serves two purposes.

1) Get Atari's into new user's hands

2) With newer chips; we could boost the speed in ways the old Asics can't handle.

 

If the computer could be flipped into a not really compatible higher speed mode (or modes) out of the box it might make it more viable as a computer for even the new [to atari] users.

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One other question:

Who needs a new atari 8bit? I've stored over 70 atari 8bit computers. And some of them are brandnew. I know: they won't last forever, but for the next 10-20 years I'm rather sure I'll have lots of fun with them. They are still easy to obtain here in The Netherlands. And not only here.

 

Serves two purposes.

1) Get Atari's into new user's hands

2) With newer chips; we could boost the speed in ways the old Asics can't handle.

 

If the computer could be flipped into a not really compatible higher speed mode (or modes) out of the box it might make it more viable as a computer for even the new [to atari] users.

 

You mean a turbo mode switch so we can toggle between 1.78979Mhz and 1.84374496Ghz (1024*original) so we can do 512 cycles of instructions every color clock?

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You mean a turbo mode switch so we can toggle between 1.78979Mhz and 1.84374496Ghz (1024*original) so we can do 512 cycles of instructions every color clock?

And here I was hoping to just get ANTIC to double its data rate so we could get a nice 80 column display! I guess I should aim higher :)

 

Stephen Anderson

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